Use finally block for Binder.restoreCallingIdentity

1. Use final for Binder.clearCallingIdentity() to protect not being overwritten.
2. Protect it in the finally block of the try statement to avoid missing restore the CallingIdentity as exception.

Bug: 189819183
Test: Manual test
Ignore-AOSP-First: prevent merge conflict
Change-Id: I2dd4cfc1aacecb0b77fa4c82b48b24b284271779